Differentials are generally designed as planetary gears, and predominantly serve the purpose of branching or dividing an input power, which is conveyed via a power input, to two driveshafts. Differentials are most commonly used in the construction of automobiles, as so-called axle differentials. In this case, drive power delivered by a drive motor is distributed by the differential to wheel driveshafts of driven wheels. The two wheel driveshafts leading to the wheels in this case are each driven with the same rotary torque—that is, in balance. When the vehicle is moving straight ahead, both wheels rotate at the same speed. In a curve, the rotation speeds of the wheels differ from each other. The axle differential enables this difference in rotation speed. The rotation speeds can vary freely; only the average value of the two speeds is unchanged. In the past, these differentials were largely designed as so-called bevel gear differentials. In addition to this design, differentials are also constructed in the form of so-called spur gear differentials. In the case of spur gear differentials, the output sun gears which function as the power output are typically coupled together via at least two planetary wheels which engage with each other and are thereby coupled into a gearing in a manner allowing rotation in opposite directions, and are designed as spur gears.
A bevel gear compensation gearing for a motor vehicle is known from DE 1 630 361 A1, equipped with a locking mechanism which makes it possible for each of the output sun gears to be fixed by a friction fit in a planet carrier, the same carrying the sun gears, via brake disks. The locking mechanism is designed in such a manner that it provides a strong locking function when unloaded, but this locking function is released as the rotary drive torque increases.
A differential for a motor vehicle is known from U.S. Pat. No. 5,326,333, having an epicyclic housing which carries a crown gear and is driven via the same. The epicyclic housing forms a ring gear toothing which is the rolling path of a first planetary arrangement. This planetary arrangement is mounted in a planet carrier which has a connector segment for a first wheel driveshaft. The planet carrier also seats a second planetary arrangement which engages on one end thereof with the first planetary arrangement, and meshes on the other end with a sun gear which has a connector segment for a second wheel driveshaft. This second sun gear can be fixed by braking via a disk pack on the planet carrier. When this braking occurs, an axial force is applied to the planet carrier, whereby the planet carrier is also axially displaced. This in turn is the result of a selective, electromagnetically-controlled braking of a support ring of a ball-ramp mechanism which revolves together with the planet carrier.
A differential is known from U.S. Pat. No. 4,679,463, wherein the locking function thereof can be adjustably modified via an annular piston mechanism. This differential has an epicyclic housing which is accommodated in a gear housing and which carries a crown gear. The epicyclic housing is driven via this crown gear. The planet carrier of a bevel gear differential is mounted in a torque-proof manner in the epicyclic housing. This bevel gear differential has a first and a second output wheel. These two output wheels can be braked by axially loading a first and a second disk clutch pack on the epicyclic housing. The annular piston mechanism is arranged fixed on the gear housing. The axial force generated by this annular piston mechanism, which does not revolve with the other components, is transmitted to the revolving region in cooperation with an axial cylindrical roller bearing which is coaxial to the gear axis.